Silent Power: Fanless PSU Roundup

I am sure that anyone would love to have a quiet power supply unit in their system. The products addressing these wishes are the fanless PSU models, which have no noise-making components by definition. Today we are going to talk about four products like that from Enhance, Kingwin, Seasonic and Silverstone.

Table of Contents

Fanless power supply units are paradoxically both innovative and conservative products. On one hand, they have to have the most advanced circuit design available at the moment to ensure highest efficiency possible because the less power is dissipated as heat, the more power can be transferred to the computer components. But on the other hand, once they are released, such products stay on the assembly line for a very long time. Why? Well, their advanced components are expensive, the high price limiting the target audience. And there are fewer competitors in this market sector as opposed to ordinary PSUs, so no one feels obliged to hurry up with the development and production of new models.

Indeed, we've got both innovative and conservative products for this review. We’ve known the Silverstone Nightjar and the fanless Seasonic X-Gold series for a few years already whereas the PSUs from Kingwin and Enhance are newcomers released in 2011.

Let’s see if the newer products are any better than the older ones, in the order of ascending wattage.

Testing Methodology

The following article offers a detailed description of our testing methodology and equipment and a brief explanation of what the specified and tested parameters of power supplies mean: X-bit Labs Presents: Power Supply Units Testing Methodology. If you feel overwhelmed with the numbers and terms this review abounds in, refer to the Methodology.

You can also go to our Cases/PSU section to check out reviews of all other PSU models we have tested in our labs.

We will mark the actual power consumption of three system configurations (discussed in our article PC Power Consumption: How Many Watts Do We Need?) in the cross-load diagrams. This will help you see if the tested PSU can meet the requirements of a real-life PC.

Testing Participants

Enhance ATX-0340N 400W

Enhance hasn’t been counted among the few makers of silent PSUs until recently. The company unveiled its first such products from the ATX0300N series at Computex 2011.

Currently, this series includes two models: the 300-watt ATX-0330N and the 400-watt ATX-0340N. We’ve got the latter model for us to test.

Exterior Design

The fanless PSU from Enhance doesn’t look like a typical product of its class that would have an aluminum top propped by huge heatsinks. It resembles Seasonic’s silent PSUs in this respect.

The ATX-0340N is almost weightless thanks to the lack of a massive heat-spreading top. Every panel of the case is perforated for ventilation.

Even the bottom panel is meshed, although there’s a layer of insulation material between it and the PCB.

There are an On/Off switch and a tiny label with product specs on the external panel of the PSU.

Circuit Design

The ATX-0340N doesn’t resemble Seasonic's products on the inside. Its black heatsinks are bigger and cover most of the PSU’s internals, making it hard to see the components. We avoid taking PSUs apart during our tests.

So, we can only see DC-DC converters with slim aluminum plates as heatsinks. That’s a solution one can expect to find in a modern fanless PSU.

We can also make out a supervisor chip PS232S through the perforated panel.

There are at least three brands of capacitors on the PSU’s output.

While Teapo components are largely blameless, Taicon and Su’scon do not enjoy such a good reputation.

Besides that, there are reputable United Chemi-Con capacitors in this PSU, although not in the output circuitry. We can’t but wonder why Enhance preferred to install worse components at the output.

Cables and Connectors

The Enhance ATX-0340N is equipped with the following cables:

One mainboard cable with a 20+4-pin connector (41 cm)

One CPU cable with a 4+4-pin connector (47+14 cm; the second half of the connector is on a 14cm stretch of the cable)

One cable with a 6-pin graphics card connector (43 cm)

One cable with three PATA power connectors (20+15+10 cm)

Two cables with three SATA power connectors on each (20+15+10 cm)

The short cables imply that the ATX-0340N is targeted at mini-ITX system cases compatible with standard PC components such as Lian Li PC-Q7 or PC-Q11. Considering this positioning, we can hardly blame the PSU for its having short cables with very few connectors. However, you should keep it in mind that the cables are going to be too short for a full-size system case, especially with a bottom PSU bay.

The odd design of the 4+4-pin connector on the CPU power cable can hardly be explained even by the mini-ITX positioning. We don't know the purpose of the additional stretch of the cable with the second half of the connector (it cannot serve as a kind of extension card for mainboards with a 4-pin CPU power connector because it's the first half of the connector that is plugged in in that case).

Specifications

You can read the product specs from the small and rather untidy label next to the mains connector. There is just no other place for it on the perforated surface of the case.

The combined load capacity of the two +12V lines is not specified but we used a load of 369 watts, or 99% of the PSU’s full output power, in our test, similar to the other products in this review.

The rest of the specs are typical enough for a modern PSU: up to 120 watts on the +3.3V and +5V rails combined and up to 2.5 amperes on the standby source.

This series of PSUs from Enhance is certified to comply with the 80 PLUS Silver standard.